PROSTATE CANCER DETECTION IN THE PROSTATE SPECIFIC ANTIGEN RANGE OF 2.0 TO 3.9 NG/ML: VALUE OF PERCENT FREE PROSTATE SPECIFIC ANTIGEN ON TUMOR DETECTION AND TUMOR AGGRESSIVENESS

Abstract

Purpose: We evaluated the positive predictive value and cancer detection rate in the prostate specific antigen (PSA) range of 2.0 to 3.9 ng/ml and assessed the value of percent free (F) PSA (FPSA) on tumor detection and tumor aggressiveness in this low PSA range. Materials and Methods: Of 3,623 men who were attending the second round of screening within the European Randomized Study of Screening for Prostate Cancer, section Rotterdam 883 had PSA values of 2.0 to 3.9 ng/ml. These men were offered laterally directed sextant biopsy. FPSA was prospectively determined from pretreatment serum. Cancers were classified as prognostically favorable and unfavorable using biopsy results and other pretreatment diagnostic features. Results: Using the PSA range of 2.0 to 3.9 ng/ml as a biopsy indication 126 cancers were detected, resulting in a positive predictive value of 17.1% and a cancer detection rate of 14.3%. By using percent FPSA and setting relative sensitivity at 95% 9% of biopsies could have been avoided. Unfavorable tumor characteristics were found in 46.9% of the men with T1C tumors. Mean percent FPSA was significantly lower in such men compared to men with favorable tumor characteristics. Of the men with percent FPSA lower than 10% 90% had unfavorable tumor characteristics. Conclusions: The PSA range 2.0 to 3.9 ng/ml is accessible for prostate cancer screening. Percent FPSA is of moderate value in avoiding unnecessary biopsies in the PSA range of 2.0 to 3.9 ng/ml. However, when assessing tumor aggressiveness in biopsy results, percent FPSA is predictive and can be used to select treatment options, such as watchful waiting.